PhD thesis

Feasibility study on high-conversion Th-U233 fuel cycle for current generation of PWRs

PhD student:

Daniela Baldova

Supervisor:

Dr. Emil Fridman (HZDR)

Division:

Reactor Safety

Period:

09/2010–08/2013

Motivation:

Thorium fuel is a recently discussed topic in the field of nuclear energy. The use of thorium as a fertile material in combination with a fissile material can supplement uranium reserves and thus provide a long-term source of energy. The feasibility of thorium based fuel utilization practically in any type of existing reactors was demonstrated.

Objectives:

The aim of this thesis is to design a high conversion Th-U233 fuel assembly applicable for current generation of Pressurized Water Reactor (PWRs). The considered fuel assembly has a typical 17×17 PWR lattice. However in order to increase the conversion of Th232 to U233, the assembly was subdivided into the two regions called seed and blanket. The central seed region has a higher than blanket U233 content and acts as a neutron source for the peripheral blanket region. The latest acts as a U233 breeder. Significantly higher initial seed fissile content leads to serious power imbalance between the regions, which will certainly require a reduction in the core power density. A detailed thermal hydraulic analysis must be performed in order to estimate the safe power density limits. However, reduction of the core power density may negatively affect the economic performance of the concept.